This article is an update to the April 2002 Sun BluePrints OnLine article, "Configuring Boot Disks With Solstice DiskSuite Software." This article focuses on the Solaris 9 Operating Environment, Solaris Volume Manager software, and VERITAS Volume Manager 3.2 software. It describes how to partition and mirror the system disk, and how to create and maintain a backup system disk. In addition, this article presents technical arguments for the choices made, and includes detailed runbooks.

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This article is a practical guide for system disk configuration. It describes
how to partition the system disk, mirror it, and create and maintain a
contingency boot disk.

We attempt to cover a wide range of availability requirements by presenting
two-, three-, and four-disk configurations. Every additional disk adds
protection. The idea is to select one configuration, based on the cost/benefit
ratio in a given situation, then use the corresponding runbook as a guide for
implementation. The SUNBEsdm package is also provided with scripts for
a fully automatic implementation.

In this document, we follow the concepts of the Sun BluePrints_ book
"Boot Disk ManagementA Guide for the Solaris_ Operating
Environment" by John S. Howard and David Deeths. We add an explicit
comparison of the use of Solaris_ Volume Manager software and VERITAS Volume
Manager (VxVM) software for mirroring the system disk.

This article is an update to "Configuring Boot Disks With Solstice
DiskSuite_ Software" by Erik Vanden Meersch and Kristien Hens (Part
#816-4526-10). The basis for the current text is the Solaris 9 Operating
Environment, Solaris Volume Manager software, and VxVM 3.2 software.

This Sun BluePrints OnLine article covers the following topics:

Hardware configuration

System disk partitioning

Two-disk configuration

Three-disk configuration

Four-disk configuration

Comparison of Solaris Volume Manager software and VxVM software

Runbook for creating the Solaris Volume Manager software state
database

Runbook for a two-disk configuration

Runbook for a three-disk configuration

Runbook for a four-disk configuration

Uses of SUNBEsdm scripts

Introduction

System disks can be protected two ways: disk mirroring and file system
backup. These two methods are complementary and cover different types of
failure. Disk mirroring keeps the system running when a disk stops responding to
commands. Backup provides a recovery path when files (or entire file systems)
are removed or corrupted.

Sun Microsystems supports two volume managers for mirroring system disks:
VERITAS Volume Manager (VxVM) software and Solaris Volume Manager software. VxVM
software is widely used on servers with a large number of disks and logical
volumes and can be considered a de facto standard.

We advocate using Solaris Volume Manager software for mirroring the system
disk, even when VxVM software is chosen for volume management of application
data. This choice is not obvious at first sight because both Solaris Volume
Manager software and VxVM software work perfectly under predictable
circumstances. The difference becomes apparent in case of disaster (defined in
this context as a situation where, due to some problem, the system no longer
boots).

It is not the intention of this document to provide an absolute best practice
for system disk configuration. Instead, our goal is to:

Present the arguments in favor of using Solaris Volume Manager software
for the system disk. These arguments are familiar to many people, who often
learned them the hard way, but we have not found them to be formally
documented.

Make life easier for the Solaris Volume Manager software user by
providing runbooks with the commands detailed and the correct sequences
provided. An engineer who routinely installs systems may not need this
information, but we believe that there is a large audience who can benefit from
some assistance in this area. We assume some level of Solaris Operating
Environment and Solaris Volume Manager software knowledge.

Runbooks and scripts are based on system disk partitioning in /,
/var, and swap. This partitioning is widely accepted as a good
practice. Because a carelessly partitioned system disk may cause considerable
trouble, we dedicate a separate section in this article to discussing the
rationale of the /, /var, and swap partitioning.